Possible to Turn Multiple PSU's into DC Power Supply?

oplin

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Jan 9, 2002
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I've looked for a while on this and haven't found an answer yet, I know you can turn a PSU into a DC Power supply for 1 psu there's tutorials on the web for that for making Lab PSU's but i'd like to take maybe 3-5 psu's 500w - 1000watts (Would be plugged into outlets with different breakers) and take all the 12volt lines and run them together to get something like 100-250amps continuous power output. This would be used to power a amplifier without it's own power supply so the current draw would be rather sporadic. Also would i be able to use the -12volt line as a ground or would i just make the ground wire on the amplifier go to a solid piece of metal or even the ground in the electrical outlet?

From what i know you should be able to combine all the 12 volt line of the psu's and have them add together, turning on the psu's shouldn't be an issue i can make a basic switch for that. Any help or ideas would be great, and bonus would be if someone knows if the 3.3 volt line could be added to the 12volt line to give an output of 15.3volts and if the 3.3volt line would be able to keep up with putting out enough amps.

The amplifier is a car stereo one reason for no power supply on it, and only reason i'm debating on hooking it up in the house is cause the thing is a little bigger than i thought it would and weighs about a 100lbs it's a JBL A3000Gti should be able to take up to 200amps at 12-15volts no problem. Oh and hte sub it's powering is a 5400LMS 18" from TC Sounds, it also seems like it's too big for the car, i was just going to pay someone to install it in the car and mod it but decided i'd just keep my old system and put it in my new car. Thanks for any help!!
 

oplin

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Really, this web page made it seem like you could,
http://www.wikihow.com/Convert-a-Computer-ATX-Power-Supply-to-a-Lab-Power-Supply
on step 14. But even if you can't it's not a huge deal. I've got a crap load of old pus's sitting around and to buy a dc power source with over 2000 watts output from what i saw was just insane. So i thought I'd just make one. If nobody chimes in and says it's a bad idea I'll probably start to proceed with my project, anyone know how i could put a 12volt load on this to test it with a multimeter? Only thing coming to mind is using it to start my car or something but i think the alternator would feed current back at it being really bad.
 

Oklahoma Wolf

PSU Warranty Voider
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Mar 22, 2005
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I've looked for a while on this and haven't found an answer yet, I know you can turn a PSU into a DC Power supply for 1 psu there's tutorials on the web for that for making Lab PSU's but i'd like to take maybe 3-5 psu's 500w - 1000watts (Would be plugged into outlets with different breakers) and take all the 12volt lines and run them together to get something like 100-250amps continuous power output. This would be used to power a amplifier without it's own power supply so the current draw would be rather sporadic

Theoretically possible, but inefficient if you plan on pulling 250A all the time. And I'd hate to see the electric bill.

Also would i be able to use the -12volt line as a ground or would i just make the ground wire on the amplifier go to a solid piece of metal or even the ground in the electrical outlet?

No to the first. You'd get 24V with only the current capacity of the -12V line. Solid piece of metal... maybe as long as you don't try to ground it to a wall socket or short it to anything else. Ground in the outlet? There's a light, sound, and fire show waiting to happen. Very dangerous.

From what i know you should be able to combine all the 12 volt line of the psu's and have them add together, turning on the psu's shouldn't be an issue i can make a basic switch for that.

Relays.

bonus would be if someone knows if the 3.3 volt line could be added to the 12volt line to give an output of 15.3volts and if the 3.3volt line would be able to keep up with putting out enough amps.

Current capacity would be limited to the lowest current capacity rail. Several units paralleled together may not like this approach and go kapow.

The amplifier is a car stereo one reason for no power supply on it, and only reason i'm debating on hooking it up in the house is cause the thing is a little bigger than i thought it would and weighs about a 100lbs it's a JBL A3000Gti should be able to take up to 200amps at 12-15volts no problem. Oh and hte sub it's powering is a 5400LMS 18" from TC Sounds, it also seems like it's too big for the car, i was just going to pay someone to install it in the car and mod it but decided i'd just keep my old system and put it in my new car. Thanks for any help!!

Honestly, I think I would either sell the amp and buy a decent pro audio amp for 115V mains, or maybe even something like an older Carver M1.5t, or put the JBL in the closet and buy the new amp anyway. Adding a bunch of old ATX units together is going to get loud and hot and inefficient.

So i thought I'd just make one. If nobody chimes in and says it's a bad idea I'll probably start to proceed with my project

To be blunt, I'd have to say it's a bad idea. Sorry :(
 

Kil4Thril

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That JBL/Crown amp can draw peaks of FAR more than 250a, especially on a tough load like the LMS voice coils can present. I would certainly build the enclosure for the 18 (VERY large sealed or infinite baffle is nice on those), and get a pro amp to run it. Check out Partsexpress.com for a good selection at decent price.
 

oplin

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Thanks for the great replies. All amps that take in 115vac whatever convert it to DC power anyway so i figured if i got some good dc power source i'd be alright. I've looked at the pro amplifiers and it'd be about 2 grand for the cheapest amplifier to power the thing decently and 5 grand for something nice which isn't a huge deal. Was really hoping that this would turn out, I think i might still end up trying this just for smitz and giggles. 80% efficiency on the psu's and when drawing current from all the lines run together the power should spread out somewhat equally, i might just try it out on 1 psu and some cheap parts first.

kil4thril, yeah i plan on having a pretty heavy duty box made for it, was planning on just making it like a coffee table or like a piece of furniture to blend in. Just won't be able to use it while the music is on.

Anybody know of a good DC power source, i think in the pro audio world they're called power plants or something?
 

quisman

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Best thing you could do is build yourself a nice big ol block supply...something about the size of amo can or larger. Good size transformer, couple diode bridges and some killer caps. DONE ! :) Hell, go for the LX model and throw in a DC voltmeter and Amp meter... Cheaper too.
Had one in college, i'm sure it's nearly as inefficient, but it ran 2 dvc rockfords made into a coffee table no problem.

edit: btw....partsexpress ROCKS !
 

oplin

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That doesn't look like it'll power the sub fully, sub can handle 5000 watts RMS power it is DVC 2ohms. If i bridged that it says it can't do 2 ohms only 4ohms in bridged mode so i couldn't get 2 of them per voice coil. I was looking for something around the lines of 2500watts rms at 2ohms and getting 2 of them 1 per voice coil or a huge one that can power 5000watts rms at 1ohm or 4 ohms stable. But that is a damn nice price on that kind of amp for the power awesome recommendation. Ideally i want something that puts out 6000watts rms so i don't stress the amp too much, it'll have to be hooked to 2 or 3 20amps breakers but that shouldn't be a problem.

Best thing you could do is build yourself a nice big ol block supply...something about the size of amo can or larger. Good size transformer, couple diode bridges and some killer caps. DONE ! :) Hell, go for the LX model and throw in a DC voltmeter and Amp meter... Cheaper too.
Had one in college, i'm sure it's nearly as inefficient, but it ran 2 dvc rockfords made into a coffee table no problem.

edit: btw....partsexpress ROCKS !

That might work, if you've got a tutorial on that or better instructions that might work.
 

dandragonrage

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Yes, go with a real amplifier.

Connecting different voltage sources is generally a bad idea.
-If in parallel (or S-P) the voltages are different, you will be driving current from the PSU with the higher voltage into the PSU with the lower voltage. Normally you try to match the voltage using .1% tolerance components as well as low resistance resistors on the outputs to lessen this problem.
-If in series (or S-P), you will short out a PC PSU because the negatives are grounded, meaning also that the negative of each PSU is connected together, so connecting the positive of one PSU to the negative another is the same as connecting the positive to the negative in the same PSU. The exception is using +12v and -12v lines together, but then you only can do that once (not adding PSUs together) and you're limited to the current on the -12v line.

Also, you do not need 250A.
 

Eulogy

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That doesn't look like it'll power the sub fully, sub can handle 5000 watts RMS power it is DVC 2ohms. If i bridged that it says it can't do 2 ohms only 4ohms in bridged mode so i couldn't get 2 of them per voice coil. I was looking for something around the lines of 2500watts rms at 2ohms and getting 2 of them 1 per voice coil or a huge one that can power 5000watts rms at 1ohm or 4 ohms stable. But that is a damn nice price on that kind of amp for the power awesome recommendation. Ideally i want something that puts out 6000watts rms so i don't stress the amp too much, it'll have to be hooked to 2 or 3 20amps breakers but that shouldn't be a problem.



That might work, if you've got a tutorial on that or better instructions that might work.
It sounds like you know very little about audio and drivers, and even less about electronics.
Just get a pro power amp and drive it. Unless you're going for competition, I promise you won't notice the difference at all between 2500W and 5000W, if this driver really takes that much. IIRC, doubling the wattage output, you only gain 3dB. On top of that, just because it's rated at 5kW RMS, and you might find a suitable amp capable of putting out 5kW RMS, you're never, ever going to sustain 5kW to that driver for very long at all.
 

oplin

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It sounds like you know very little about audio and drivers, and even less about electronics.
Just get a pro power amp and drive it. Unless you're going for competition, I promise you won't notice the difference at all between 2500W and 5000W, if this driver really takes that much. IIRC, doubling the wattage output, you only gain 3dB. On top of that, just because it's rated at 5kW RMS, and you might find a suitable amp capable of putting out 5kW RMS, you're never, ever going to sustain 5kW to that driver for very long at all.

Whole idea of using the psu's was to avoid buying a pro amplifier. There are plenty out there that can put out 5000watts rms for long periods of time, i just didn't want to spend the 2-20 grand on the thing when i have a amplifier that would work, it just needs a huge dc power source. There's plenty of people that have done this with battery chargers or DIY stuff so that's where i was trying to go with this.
 

ALL4AMD

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Whole idea of using the psu's was to avoid buying a pro amplifier. There are plenty out there that can put out 5000watts rms for long periods of time, i just didn't want to spend the 2-20 grand on the thing when i have a amplifier that would work, it just needs a huge dc power source. There's plenty of people that have done this with battery chargers or DIY stuff so that's where i was trying to go with this.

i say u can do it. just use some lightning caps and sealed car batterys to filter the dc
 

oplin

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Car batteries would work, and just charge them over night? That might actually be a great idea some of the yellow top batteries can put out 200+ amps, get 3 of them, wire them up, system would play for 5-7 hours longer than i would need it for, and just charge it over night with a little battery charger. As for the caps that wouldn't do anything, as you need to charge the cap to a higher voltage than the batteries for them to even kick in and at the wattage i'd be pulling it wouldn't last for more than a micro second. But battery idea is a good simple way to test the amplifier and stuff. People have made their houses run on 12volts before with car batteries linked together, just that these would need to be hidden somewhere.
 

Kil4Thril

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Just because those massive LMS coils can dissipate the heat from 5000+ watts (and they will), does that mean you NEED 5000+? Absolutely not. Have someone model up the enclosure in Bass Box Pro and see where the point of power compression begins (in your chosen enclosure). Also, that JBL would drain a huge bank of batteries in a few short minutes at full tilt. A standard DC power supply to keep up with the draw you'd be pulling wouldn't even run on standard US home wiring. You'd have to update and run a dedicated line. Maybe Meanwell could build you something, or call Scottie Johnson at Powermaster. Good luck, I hope you aren't disappointed.
 

dragonslayer45895

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i honestly would be scared to run 5000w in a home....blasting out all windows in the room anybody? my dad burst 2 windows in his room with 1250w pumping out of 2 speakers.........so......reinforced windows would be key too!

As for a power supply, listen to the fellas...they know there stuff!
 

oplin

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It's pretty rare for windows to break with stereo's in a car actually i think it's almost impossible. The house i can see happening cause they're alot less durable and if you hit the resonating frequency of the window it'd shatter, i plan on trying to do a huge ported sub that goes pretty low so as long as the windows are open it shouldn't be an issue but you should be able to tell fi they're going to shatter before you crank it up all the way.

There's a couple comapanies that make ac to dc power supplies that are big enough for what i want but i'm not positive on the cost of them.
 

ALL4AMD

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Car batteries would work, and just charge them over night? That might actually be a great idea some of the yellow top batteries can put out 200+ amps, get 3 of them, wire them up, system would play for 5-7 hours longer than i would need it for, and just charge it over night with a little battery charger. As for the caps that wouldn't do anything, as you need to charge the cap to a higher voltage than the batteries for them to even kick in and at the wattage i'd be pulling it wouldn't last for more than a micro second. But battery idea is a good simple way to test the amplifier and stuff. People have made their houses run on 12volts before with car batteries linked together, just that these would need to be hidden somewhere.

do u know anything about electronics? http://electronics.howstuffworks.com/capacitor.htm
 

Kil4Thril

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It's pretty rare for windows to break with stereo's in a car actually i think it's almost impossible. The house i can see happening cause they're alot less durable and if you hit the resonating frequency of the window it'd shatter, i plan on trying to do a huge ported sub that goes pretty low so as long as the windows are open it shouldn't be an issue but you should be able to tell fi they're going to shatter before you crank it up all the way.

There's a couple comapanies that make ac to dc power supplies that are big enough for what i want but i'm not positive on the cost of them.

They're absolutely outrageous, and to get the current you'll need, a dedicated 220v line would be necessary (or a gasoline generator).

I found one that's only 90A at 12v (Stinger), and it was over $700. That combined with a bank of batteries MAY work without problems, but the batteries will still drain under extended usage.
 

oplin

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I know what a capacitor does, it only works to maintain steady current draw, meaning if the voltage doesn't drop below 12 volts the capacitor isn't used at all. In a car they're used cause the alternator puts out 14.4 volts and the battery is 12 volts so when the amp draws more current then the alternator puts out the capacitor steps in and tries to maintain the 14.4 volts. If i was using all 12 volts batteries and they can put out 100-200amps there wouldn't likely be any voltage drop, as for it cleaning up any noise it'd be useful. If the voltage doesn't drop it won't be used at all, if I'm wrong outline let me know, also the cost of a capacitor wouldn't be justified, also the amp has capacitors in it.

http://www.bcae1.com/capacitr.htm

As for powering the ac/dc power source using i'd be using 2 20amp breakers dedicated to it, i don't plan on running this full blast.

My current car battery a yellow top can run the stereo for over an hour with it turned up pretty loud, so i figure 4-5 should be able to last for a movie or longer. Car has a 4000 watt amp and 1000 watt amp which is about 2500 watts RMS power based on what other people have posted for their birth sheets.
 

Kil4Thril

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I know what a capacitor does, it only works to maintain steady current draw, meaning if the voltage doesn't drop below 12 volts the capacitor isn't used at all. In a car they're used cause the alternator puts out 14.4 volts and the battery is 12 volts so when the amp draws more current then the alternator puts out the capacitor steps in and tries to maintain the 14.4 volts. If i was using all 12 volts batteries and they can put out 100-200amps there wouldn't likely be any voltage drop, as for it cleaning up any noise it'd be useful. If the voltage doesn't drop it won't be used at all, if I'm wrong outline let me know, also the cost of a capacitor wouldn't be justified, also the amp has capacitors in it.

http://www.bcae1.com/capacitr.htm

As for powering the ac/dc power source using i'd be using 2 20amp breakers dedicated to it, i don't plan on running this full blast.

My current car battery a yellow top can run the stereo for over an hour with it turned up pretty loud, so i figure 4-5 should be able to last for a movie or longer. Car has a 4000 watt amp and 1000 watt amp which is about 2500 watts RMS power based on what other people have posted for their birth sheets.

The bolded and following statements are absolutely false. Voltage has nothing to do with a capacitor. It will only sit at the voltage to which it is charged. Most car audio capacitors are 16-20v to handle the overvoltage situations competitors like to use (for amps with unregulated supplies, this will give you more output until you reach the limits of the amp). The only thing a cap really does effectively in a car audio environment is drain your wallet. If the charging system couldn't keep up with the current demands of the system, how the hell can it magically do so after adding another device that draws from it?

Oh, I also found a few cheaper power supplies. They're made by Pyramid, though :( I haven't heard anything about the large ones, but a lot of people were using the smaller ones on test benches and to charge battery banks.
 

ALL4AMD

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The bolded and following statements are absolutely false. Voltage has nothing to do with a capacitor. It will only sit at the voltage to which it is charged. Most car audio capacitors are 16-20v to handle the overvoltage situations competitors like to use (for amps with unregulated supplies, this will give you more output until you reach the limits of the amp). The only thing a cap really does effectively in a car audio environment is drain your wallet. If the charging system couldn't keep up with the current demands of the system, how the hell can it magically do so after adding another device that draws from it?

Oh, I also found a few cheaper power supplies. They're made by Pyramid, though :( I haven't heard anything about the large ones, but a lot of people were using the smaller ones on test benches and to charge battery banks.

its not just that. when an amp draws peak power the cap releases energy faster than a battery in a car 15ft away. why do u thing ur lights dim without a cap? it smoothes out the load and thats one reason why its called filtering.
 
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